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In patients with ion channel disease the predominant arrhythmias are polymorphic ventricular tachycardias (VT), torsade de pointes tachycardia and ventricular fibrillation (VF). In only extremely rare cases is very rapid monomorphic ventricular tachycardia observed. This is why implantable cardioverter-defibrillators (ICDs) should always be programmed for treatment of VF only with high detection rates to avoid inappropriate discharges. In idiopathic VF and catecholaminergic polymorphic ventricular tachycardia (CPVT), no baseline electrocardiographic abnormalities can be detected, whereas in Brugada syndrome, long QT syndrome, early repolarisation syndrome and Anderson-Tawil syndrome alterations of the baseline ECG are very important to identify patients at risk.

History: A 17-year-old female student presented in our emergency room after a seizure with motoric fits and enuresis. It was the second event of this kind within 3 weeks., Investigations: The resting ECG on admission showed sinus bradycardia at 45 bpm and a remarkable repolarisation with notched or bifurcated T waves in several leads. Further clinical investigations were unremarkable., Treatment and Course: As an arrhythmogenic syncope (bradycardia or tachycardia related) was presumed, beta-blocker therapy was initiated and an implantable loop recorder (ILR) was inserted. Approximately one year after the index event, the student was brought to the emergency room by ambulance after another seizure. Interrogation of the ILR revealed torsade de pointes tachycardia with spontaneous termination after 1 min and 24 s. A dual-chamber ICD for secondary prophylaxis of sudden cardiac death was therefore implanted and the dose of beta-blocker was increased. Genetic analysis for long-QT-syndrome (LQTS) was negative with regards to the most frequent known gene loci. For 6 months the patient has been free of symptoms., Conclusion: Arrhythmogenic syncopes can clinically resemble epileptic seizures ("convulsive syncope"). During basic work-up of syncope, the 12 lead ECG may provide valuable clues indicating an arrhythmogenic cause of syncope, showing excitation as well as repolarisation abnormalities. If an arrhythmogenic cause of syncope is suspected but ECG documentation as a proof of diagnosis is missing, implantation of an ILR can be useful. In LQTS, multiple gene mutations are known but cover only a fraction of clinical LQTS., (© Georg Thieme Verlag KG Stuttgart · New York.)

Prolongation of the ventricular repolarisation manifests itself as a prolongation of the QT intervall on the surface ECG and represents a major risk for a special form of ventricular tachycardia called "torsades de pointes". Torsades de pointes are often self limited and are associated with palpitations, dizziness or syncope. Degeneration into ventricular fibrillation and sudden cardiac death can occur. In addition to the various forms of the congenital long QT syndrome many drugs, such as antiarrhythmic drugs class IA and III, antibiotics, antihistamines, antidepressants, and methadone are known to prolong the QT interval. Most of these drugs block a specific potassium channel substantially involved in the ventricular repolarisation. In addition, drug interaction or disturbances of drug metabolism may play a major role in the acquired form of the long QT syndrome. The individual risk and the potential of a pharmacologic substance to prolong the QT interval are not predictable. Certain risk factors identify patients at higher risk for drug-induced prolongation of the QT interval. Correctable factors include electrolyte disorders (e.g. hypokalemia) and concomitant administration of different QT prolonging drugs. External defibrillation is the therapy of choice in the hemodynamic unstable patient presenting torsades de pointes. In hemodynamic more stable patients application of intravenous magnesium can terminate torsades de pointes (membrane stabilizing properties). Temporary external or transvenous pacing at high heart rate might terminate incessant torsades de pointes by decreasing QT interval. Repeated ECG controls during therapy with QT prolonging drugs are mandatory, especially when drug doses are changed, additional drugs are prescribed, or in case of vomiting and diarrhea. QT prolongation in individual medical therapy is not always predictable. Therefore, updated lists of drugs with the potential of QT prolongation are available on the Internet (e.g. www.qtdrugs.org ).

Prevention and therapy of cardiovascular diseases have undergone enormous changes over the last decades. However, ventricular tachycardias (VT) still pose a major problem in a number of cardiac patients. Analysis of the etiology and mechanism of the tachycardia is of paramount importance for initiation of specific therapies. The morphology of VTs on the surface ECG can be either polymorphic or monomorphic. Polymorphic VTs have a constantly changing QRS-morphology due to the variable ventricular activation, without specific origin. This kind of VT is mainly caused by an acute, often reversible condition, such as ischemia or QT-prolongation. These VTs are potentially malignant, they cannot be treated by catheter ablation. In contrast, monomorphic VTs have a constant QRS-morphology, indicative of repetitive ventricular depolarisation in the same activation sequence. This kind of VT is either caused by focal abnormal activity (triggered activity, automaticity, micro-reentry) or by an arrhythmogenic substrate (macro-reentry). Focal idiopathic VTs usually have a benign prognosis and catheter ablation is potentially curative. The majority of ventricular arrhythmias, however, are substrate-related reentry tachycardias, most commonly based on an infarct scar Therapy of first choice for these patients is the treatment with an implantable Cardioverter/Defibrillator (ICD). Catheter ablation is indicated in case of drug refractory recurrent VTs triggering repeated ICD therapies. The different therapeutic strategies are not alternative but complementary options in many patients.

History and Admission Findings: A 69-year-old somnolent woman developed severe heart failure, aggravated by recurrent episodes of ventricular tachycardia. The patient showed central and peripheral edema. 24 hours earlier, she had suffered cerebral seizures that were successfully terminated by phenytoin. For 13 years, persistent atrial fibrillation had been frequency-controlled with antiarrhythmic drugs (verapamil and glycosides) and treated by oral anticoagulation. In addition, there had been long-term anti-depressant therapy with the tetracyclic agent maprotiline., Investigations: Torsade de pointes tachycardia was documented in the electrocardiograms. In addition, the QT interval was extensively prolonged (QTc = 0.70 sec). Neither electrolyte disturbances nor acute cardiac ischemia were seen. Echocardiography revealed a highly reduced ejection fraction of 25 % and a moderately dilated left ventricle. Angiography showed a collateralized occlusion of the right and plaques of the left coronary artery., Treatment and Course: Repeated torsade de pointes tachycardia resulted in hemodynamic compromise and were terminated by defibrillations. After intravenous magnesium and xylocaine administration as well as with termination of maprotiline and antiarrhythmic co-medication, QT prolongation decreased. In addition, the recurrent torsade de pointes tachycardia stopped. Subsequently, however, there were several bradycardia episodes, QT duration remained long. Accordingly, a VVI pacemaker was implanted. Up to now, the patient is doing well., Conclusions: With antidepressant therapy, a risky constellation including comorbidity and interactions with potentially arrhythmogenic drugs may lead to QT prolongation. Medication that delays conduction or causes bradycardia may generally favour torsade de pointes tachycardia. In case of indispensable multi-drug therapy, regular clinical as well as electrocardiographic monitoring with special emphasis on QT interval is mandatory.

A 29-year-old otherwise symptom-free patient had undergone a partial thyroidectomy 5 years ago followed by an episode of ventricular tachycardia and (after lidocaine injection) ventricular fibrillation requiring external defibrillation. No cause for the arrhythmias had been found at that time. Two subsequent syncopes led to her hospitalization. An asystole occurred while she was being monitored, and during the resuscitation there were several periods of ventricular fibrillation, which responded to external defibrillation. Subsequently several episodes of self-limiting ventricular tachycardia were recorded. A long QT syndrome with torsade-de-pointes tachycardia was diagnosed on the basis of typical ECG changes (QT interval 545 ms). Extensive diagnostic tests failed to find a cause. To prevent further tachycardias she was given propranolol, 40 mg three times daily, and an automatic defibrillator was implanted as a precaution. But no defibrillator discharge has so far been required (more than 10 months).

Torsade de pointes (TDP) is a polymorphic ventricular tachycardia with a particular electrocardiographic pattern of continuously changing ("twisting") morphology of the QRS complex occurring in the setting of delayed myocardial repolarization (i.e., prolongation of the QT interval). TDP may develop in the setting of an idiopathic disorder (Jervell/Lange-Nielsen syndrome, Romano-Ward syndrome, sporadic long QT syndrome) or may be induced by pharmacologic agents which prolong the QT interval, as well as by other clinical circumstances under which repolarization is delayed (e.g., hypokalemia, hypomagnesemia, bradycardia) (acquired long QT syndrome). Since the treatment of TDP strongly differs from that of conventional ventricular tachycardia, correct diagnosis is critical as it guides the treating physician in selecting the appropriate mode of therapy. In this paper mainly the electrocardiographic criteria presently used for the correct identification of this unusual form of ventricular arrhythmia are presented. Additionally, the potential mechanisms and therapeutic modalities of TDP are discussed.

The case of a 36-year-old woman with suspected idiopathic long QT syndrome is reported. Diagnosis was made late after syncopal attacks and several episodes of resuscitation had occurred. Although therapy with a beta-blocking agent was initiated and a cardioverter/defibrillator was implanted, the patient died, due to a hydrocephalus internus resulting in cerebral damage. Diagnostic and therapeutic problems in idiopathic long QT syndrome are discussed.

Two well documented cases of torsades de pointes under amiodarone therapy are discussed. This special form of ventricular tachycardia is also known as "twisting around the points" or "cardiac ballet". Our first case involves recurrent torsades de pointes manifesting almost 2 weeks following onset of amiodarone therapy. They were successfully treated by overpacing. In the second case the isolated torsade de pointes was probably not caused by the longlasting and successful use of amiodarone but reflected severe ischemic heart disease and slight hypokalemia. This was confirmed in the one year follow-up, as torsade de pointes was no longer present despite increased dosage of amiodarone. Amiodarone-induced torsades de pointes is very rare. Most cases reported in the literature are poorly documented or were caused by other factors (electrolyte disturbances, other antiarrhythmic medication). If amiodarone has been administered as a matter of utmost necessity, other etiologies must be excluded or eliminated before amiodarone therapy is stopped when torsades de pointes occurs. Torsade de pointes due to amiodarone arises independently of the duration of therapy, the administered dosage and the extent of QT-prolongation. Holter monitoring does not allow a prediction and the benefit of electrophysiological studies is still controversial. The management of patients with amiodarone-induced torsades de pointes includes administration of magnesium and, frequently, overpacing. Due to the long half-life of amiodarone, prolonged temporary pacing may be required. General experience suggested that amiodarone can be used safely in patients who have developed torsades de pointes with other agents.

An unusual case of familial Long QT syndrome is reported. After a longstanding symptom free interval this eight year old girl experienced multiple episodes of malignant ventricular arrhythmias including ventricular tachycardias of the torsades-de-pointes type and ventricular flutter. The treatment with beta- and alpha-blocking agents, phenytoin, calcium antagonists, clonidine and magnesium in increasing doses and varying combinations was unsuccessful. A left sided cardiac sympathectomy failed also to control the life threatening ventricular arrhythmias and to decrease the relative high mean heart rate. Finally a consecutive right cardiac sympathetic denervation in combination with an experimental class I antiarrhythmic agent led to a subjective and objective improvement in the patient's condition which allowed discharge from hospital. Despite a symptom free interval of four months and nearly normalized Holter ECG results the longterm prognosis remains unclear. This unusual case discloses interesting features, because 1) it supports the theory of an intracardiac cellular anomaly rather than the imbalance hypothesis, 2. chronic beta-blocker treatment possibly resulted in an up-regulation of beta-adrenergic receptors which made beta-blocking agents ineffective despite high doses, and 3. an consecutive right sided cardiac sympathectomy resulting in bilateral cardiac sympathetic denervation had to be done-an intervention which is seldom performed in the Long QT syndrome.